Field of the Invention
The present invention is related to an image compositing apparatus that composes a plurality of images captured while changing focal positions.
Description of the Related Art
Image capturing apparatuses such as a digital camera etc., have a function of obtaining a plurality of pieces of image data so as to achieve image quality that cannot be achieved by a single image. Patent Document 1 discloses a technique of obtaining a plurality of pieces of image data by moving the focal position and composing the obtained pieces of image data so as to obtain an image with a large depth of field. This type of photography is also referred to as focus bracketing photography.
It is known that magnification changes in images are caused by image-pickup optical systems and that optical aberrations occur in different amounts between pieces of image data of different focal positions. For example, Patent Document 2 discloses a technique of correcting each of a plurality of pieces of image data on the basis of data that is obtained by quantifying these aberrations in advance. Further, a distortion aberration and a chromatic aberration of magnification, which depend upon the image height, occur in a captured image in response to the lens characteristic. Also, Patent Document 3 discloses a magnification changing process for correcting a magnification change caused by aberration correction because the above aberration correction changes the magnification.
[Patent Document 1] Japanese Laid-open Patent Publication No. 2008-271240
[Patent Document 2] Japanese Laid-open Patent Publication No. 2001-257932
[Patent Document 3] Japanese Laid-open Patent Publication No. 2009-105621